Bendamustine, 4-[5-[bis(2-chloroethyl)amino]-1-methylbenzimidazol-2-yl]butanoic acid:
is marketed as the hydrochloride salt under the trade names RIBOMUSTIN and TREANDA and is a compound that has been used successfully for the treatment of blood cancers such as chronic lymphocytic leukemia, Hodgkin's disease, non-Hodgkin's lymphoma, and multiple myeloma. These products are administered as intravenous infusions.
Use of bendamustine for the treatment of solid tumors is limited, however, by the compound's chemical instability in aqueous environment. Indeed, bendamustine has been reported as having a half-life of only about 6-10 minutes in vivo. As a result, circulating levels of bendamustine are not sustained for a long enough time for bendamustine to reach tumors outside of the circulatory system. Methods for increasing the circulation time of bendamustine are needed.